Definitions: Fracking is hydraulic fracturing, a process where water (or similar liquid) is pumped down a well under high pressure. It is a proven technology in use for over 60 years. The pressure splits the rock like an axe splits a log, and creates fractures (cracks) in the rock containing the oil or gas.
The fractures grow in length and height, and act as conduits to allow the oil or gas faster access to the well. This means a higher production rate. The fractures are a bit like those you see in the sidewalk or roadway. They’re long but not very wide. Typical fracture widths are less than half an inch, and usually much smaller.
The revolution that is called shale gas or shale oil has been successful because many frac treatments are pumped one at a time along the length of a horizontal well.
This new technology has opened up enough conduits in the shale to get the gas out fast enough to make a profitable well. The revolution took off in the early 2000’s in the Barnett shale close to Fort Worth, Texas. Some wells have even been drilled under the DFW airport.
The benefits: The success in the Barnett has been transferred to several other shale basins, and this has caused the US supplies of oil and gas to turn upward after many years of decline. It has also forced the price of natural gas down.
The USA is becoming less dependent on foreign oil, and saving some of the massive dollar amounts it sends to other countries to buy the oil. In a few years the US may be exporting natural gas in liquefied form (called LNG) and actually making money. Although, building a new LNG train/terminal costs a few billion dollars (yes that’s billion) as Australia has recently found out.
The booming shale plays in the US are large job resources. The Bakken shale in North Dakota, and the Eagle Ford shale in south Texas are two examples. If you are out of work and go there, you will be able to find a job. A huge number of jobs has been provided by the shale oil and gas industries since the revolution started.
Burning natural gas in electrical generators is cheaper than burning coal, and generators are slowly changing over. Natural gas burns cleaner than coal or oil, and generates only about half of the CO2 that goes into the atmosphere.
Thus it is viewed by many as a half-way house for limiting greenhouse gases and their negative effects. Until the country gears more to sustainable methods such as wind turbines and solar collectors. Cars can also be run on natural gas, and many do in other countries such as Australia and India. However the US has been slow to move forward in this area.
Perceived problems: I shall address these separately.
Fracking contaminates surface water or water in aquifers. This is highly unlikely since most shale plays are deeper than 5,000 ft, and aquifers are normally shallower than 2000 ft. It is known that the fractures, although long and thin, do not usually grow upward more than a few hundred feet. This has been established by microseismic data. The fractures don’t get anywhere near the 2000 ft level of the deepest aquifers.
However, gas has occasionally been found in aquifers or at the surface, and this is generally due to poor well construction. After a well is drilled, steel casing is installed from the surface to the bottom of the well. Cement is then poured in outside the casing to fill the gaps between the casing and the rock formations.
If the casing of a well is not properly cemented against the rock all the way to the surface, the gas can seep upward. A situation like this caused the blowout of the Macondo oil well in the Gulf of Mexico a couple of years ago, which led to the release of large volumes of oil into the ocean. Oil companies need to be held accountable for contamination as a result of poorly cemented casing.
A tiny amount of seismic energy is released during a frac job. Hundreds of microseismic energy bursts may be recorded, but each is only equivalent to a gallon of milk falling off a kitchen counter. No damage has been reported in over a million frac jobs.
Shale fracking often uses ‘water fracs’ which means water containing a small amount of chemicals, The concentration is less than the chemicals in a swimming pool. Plus, sand grains called proppant to hold the fractures open after the high pressure diffuses away. In fact the concentration of water plus proppant is 99.5% of the total fluid injected.
The chemicals are to make the water slick (surfactant or “soap”), to prevent the shale in the rock from swelling. Also, to guard against bacterial growth underground (biocide) and things like that. Many of these additives are used in household products or foods that we eat. Although some shale fracs are pumped with more thickeners (gels) in the water. Therefore a higher percentage of chemicals, the chemicals stay deep in the ground because the fractures stay deep in the ground.
Even though huge volumes of water are used when fracking a long horizontal well. Lengths typically less than 5000 ft, but some are up to 10,000 ft long. The liquid cannot travel far from the fractures because shale rock is incredibly tight. the fractures stay at great depths as explained above. Approximately 30-50% of the injected water is recovered.
The huge volumes used in fracking can be a drain on a local water supply if city water is used. However, progress is being made toward using saltier water, such as water produced from other wells, or even sea water.
The intensive development of a shale play with many wells may lead to air pollution (as well as noise pollution) due to exhaust from engines that pump the frac fluid down the well. Also, due to escape of gas from the well structure (although this leakage is normally minor). Some oil wells still deliberately flare gas, but this is monitored by the Environmental Protection Agency (EPA).
Last is disposal of water produced by shale wells. When after fracking a well is turned on to production, some of the water produced is frac water and some is water that was originally in the shale. Apart from surface disposal, which is regulated and monitored by state environmental departments, there is underground disposal down specially designed wells.
If there are a lot of disposal wells receiving liquid at the same time, this may lead to a buildup of pressure over an area large enough to induce minor earthquakes. By minor is meant less than about 4 on the Richter scale which means the quakes may be felt at the surface but cause no damage. This appears to be the case in Ohio in 2011. Note that a 6 earthquake, which is 100 times more powerful, can cause serious damage.
Oil companies are actively trying to invent fracking schemes that use much less, or no water, and therefore lead to less produced water which has to be disposed of. In addition, guidelines have been proposed for reducing the likelihood of earthquakes. One such is to measure any seismic activity near the disposal wells. Then, to limit the injection of water into disposal wells if/when earthquakes are first observed. Finally, no earthquake induced by fluid disposal has caused significant injury or damage even though 140,000 disposal wells have operated safely in the US for decades.
P.S. I just heard (3 April) from a reliable source that Oklahoma recently registered a disposal-induced earthquake of magnitude over 5, and it DID cause some property damage. This supports deployment of the guidelines mentioned above, and it does seem rather urgent to do this. There would be a huge outcry if even one person were killed in such an earthquake.
Safer wells will ease legitimate concerns that have been raised, and allow the US to enjoy the many benefits. When using the new technology, oil and gas companies need to keep their hands clean. Safety issues that are being addressed include:
• Construct wells with cement that tightly bonds the casing to the rock all the way along a well to the surface. Also, with tight joints to prevent leakage in the above-ground “Christmas tree”.
• Work with the EPA to define new standards to control all emissions from oil and gas well activities.
• Learn how to re-use produced water for the next frac job and thus conserve water. And figure out ways to reduce or replace frac water with other fluids. Like, liquefied natural gas which would eventually come out of the well with the original gas in the shale formation.
• Impose guidelines to monitor potential earthquakes near disposal wells, and limit injection volumes and rates accordingly.
Western Europe imports about a third of its natural gas from Russia (and the pipeline comes through Ukraine!) Germany imports 40%. Thus Europe doesn’t seem to have a winning hand for installing economic sanctions against Russia for the Crimea takeover.
At the same time some countries like France have prohibited the use of fracking, which is part of the new technology needed to develop shale gas. Since shale gas might serve to replace Russia’s gas, maybe Europe should rethink their fracking politics. However, other countries like Poland are steaming full ahead to develop their large deposits of shale gas.
The Gray Nomad.
Probing the practice of Christian believers……
The earth is the LORD’s, and the fulness thereof. The world, and they that dwell therein. For he hath founded it upon the seas, and established it upon the floods. Who shall ascend into the hill of the LORD? Or who shall stand in his holy place? He that hath clean hands, and a pure heart. Who hath not lifted up his soul unto vanity, nor sworn deceitfully (Psalm 24).
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